Question: Simplify the following expression: $n = \dfrac{-4r + 9}{5r + 2} \div \dfrac{1}{4}$
Explanation: Dividing by a number is the same as multiplying by its inverse. $n = \dfrac{-4r + 9}{5r + 2} \times \dfrac{4}{1}$ When multiplying fractions, we multiply the numerators and the denominators. $n = \dfrac{(-4r + 9) \times 4} {(5r + 2) \times 1}$ $n = \dfrac{-16r + 36}{5r + 2}$